The invention relates to a water treatment arrangement which can, for example, be used with a sewer cleaning vehicle.
Municipal vehicles, especially sewer cleaning vehicles, are used mainly to clean sewers and the like. They are also used to clear sewer clogs, for street cleaning after heavy precipitation with trash accumulation, floods, for sucking dirt and mud out of containers and tanks, and so forth. They comprise a tank which is mounted on the chassis of a truck and which is divided into several chambers. The generally cylindrically made, barrel-like tank can be arranged horizontally. In one version of these sewer cleaning vehicles known from the prior art, the tank viewed from the back end of the vehicle has a first larger chamber, in which stones, gravel and mud settle out of the mud-water mixture which has been picked up by a suction hose. The mud chamber in the direction of the cab has a separation chamber in which the mud-water mixture which has been entrained with suction air is separated from the latter and the water is separated from the mud. Toward the cab a fresh water tank follows; it is used to store fresh water which is used to clean sewers, tanks and barrels which have been cleaned beforehand with a high pressure water jet. There is a separate high pressure pump for producing the pressure which is necessary for this purpose. The negative pressure which is necessary for sucking up the water-mud mixture is produced by a vacuum pump, for example a water ring pump, which is located within the fresh water chamber in the known embodiment.
The fresh water chamber and the separator occupy a large part of the tank volume. This volume is lacking in the mud chamber for holding the suctioned mud. For this reason the mud chamber reaches the maximum fill level more quickly and the cleaning process must be interrupted to empty it. Moreover, the mud chamber which can assume a relatively great weight in operation is located very far to the back on the vehicle. In conjunction with the boom located on the back end of the tank for the mud suction hose and the reel mounted on the end of the tank for the high pressure hose, a very unfavorable weight distribution of the sewer cleaning vehicle results. This can lead to excess wear on the rear wheels of the vehicle. The unfavorable center of gravity can even lead to the steerability of the vehicle being adversely affected.
To remedy this situation, in another known sewer cleaning vehicle it has been proposed that a water treatment device which includes the separator and fresh water tank be moved out of the horizontal cylindrical tank. In this arrangement, between the cab and the tank above the vehicle frame, a space is left open and holds the fresh water tank, the separator, for example a cyclone, and the vacuum pump, generally a water ring pump. The water ring pump is located between the separator and the fresh water tank which are mounted on the right and left on the vehicle frame. This arrangement makes it possible to make the mud tank longer. The increase in the volume provides for longer, uninterrupted operation and also improves the weight distribution on the vehicle. The disadvantage in this arrangement is that the width of the vehicle is relatively great due to the lateral arrangement of the separator and the fresh water tank. This can lead to adverse effects in use of the sewer cleaning vehicle under the narrow conditions of European municipalities.